Engine starter



Oct. 19, 1937. c. E. WHEELER 2,095,570

I ENGINE STARTER.

Filed June 25, 1934 Patented Oct. 19, 1937 UNITED STATES PATENT} OFFICE 2,096,570 ENGINE STARTER Charles E. Wheeler, Chicago, Ill. Application June 25, 1934, Serial No. 732,188

8 Claims.

This invention relates to a starter for internal combustion engines and has for an object the provision of a simple, efficient and reliable device that may be manufactured at a low cost.

Another object is to provide a new and improved engine starter particularly adapted for automotive use and embodying a helical spring element of novel construction through which the driving torque is transmitted to a drive pinion.

In starting devices of the type contemplated a helical spring element performs a plurality of functions. First, the helix thereof forms a guideway and coacts with a driving arm on the driving pinion to produce longitudinal movement of the pinion along the shaft of the starting motor to engage the pinion with the ring gear of the engine and to disengage the pinion therefrom. Second, the helical element provides, through the winding or twisting of the element between the anchored ends thereof, a sufficient yield to take up any shock between the electric starting motor and the engine, thus providing a smooth quiet starting operation whenthe pinion is fully engaged with the ring gear of the engine to be started. Third, should the pinion fail to mesh with its initial contact with the gear teeth of the ring gear, the helical element will yield and permit the proper meshing.

It is another object of the invention to provide an'engine starter embodying a helical spring element made of a wire of relatively small cross section, permitting it to be formed into a coil of the desired size and at the same time permit of a length sufiicient to give the necessary yield in operation and to contact under abnormal loads against a supporting sleeve extension on the pinion. In this manner it assists in the driving of the pinion by gripping the sleeve.

Another object is to provide a device of this character with means for supporting the helical element throughout its entire coiled length, and particularly under load so that there is no possibility of the coils collapsing.

Another object is to provide a new and improved starter embodying a driving member provided with projecting arms having cylindrical sockets for receiving the adjacent ends of a helical spring element so that the driving member can, with equal facility, receive either a right or left-hand helical element. 7

Further objects include, in a device of this character, the provision of means for limiting the withdrawal movement of the pinion and its driving arm, and the provision of a spring structure formed from a single length of wire doubled back so as to provide a double coil forming a helical guideway and a driving loop at the end of the guideway, and having circular eyes or loops on the ends for pivotal attachment to the driving 5 member.

Other objects will become readily apparent from the following detailed description taken in connection with the accompanying drawing, in

which: 7

Fig. 1 is a fragmentary elevation showing a pref-erredfo-rm of the invention associated with an electric motor drive shaft and a driven member, such as the ring gear on the flywheel of an engine, the parts being in their normal or idle position.

Fig. 2 is a section along the line 2-2 of Fig. 1.

Fig. 3 is a central longitudinal section through the device shown in Fig. 1, but with the pinion engaged with the ring gear. r

Fig. 4 is a section along the line 44 of Fig. '3.

Fig. 5 is a view similar to Fig. 4 showing the relative positions of the parts during the starting operation.

Fig. 6 is a view of a modified form of helical element.

While I have shown in the drawing and shall herein describe in detail a preferred embodiment of the invention',together with a modification, it is to be understood that I do not intend to limit the invention to the specific forms disclosed but aim to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended. claims.

In the preferred form of the invention illustrated in Figs. 1 to 5, a drive shaft l0 carries a pinion H which is arranged to form a driving connection with a driven member 12. The shaft it may be the armature shaft of an electric starting motor, and generally the driven member I2 is an engine flywheel or other rotatable part having suitable gear teeth forming a ring gear. The pinion H is formed on one part l3 of a two-part sleeve (the other part being designated by the numeral l4) and is arranged to be driven by the shaft it! by means comp-rising a driving member i5 and a helical spring element [6. The pinion slides directly on the drive shaft Ill so as to permit of a minimum diameter pinion'with a small number of teeth.

The driving member I5 is shown in the form of a disk, having a hub portion I5 and a pair of diametrically opposed; longitudinally extendingarnis l5". The member 15 is preferably se-:

cured to the drive shaft ID by means of a key IT, to prevent relative rotary movement therebetween, and by means of a set screw l8 to prevent longitudinal movement of the driving member on the shaft. The arms l5" are formed with cylindrical, drilled openings I9 forming sockets for receiving the adjacent looped ends of the helical element I6, as hereinafter more fully described.

The helical element I6 is in the form of a double coil spring having attaching eyes or loops I6 fitted into the sockets I9 of the driving member I5. The coils of the spring are positioned adjacent each other so as to provide a helical slot or guideway 2% into which an integral projecting lug or driving arm I3 on the sleeve part l3 extends. In the form illustrated in Figs. 1 to 5, the helical element is made from a single piece of spring material in ribbon form, doubled back at I6" to form a driving loop or hook and wound on edge to a size larger than the sleeve I3I4 which it surrounds. The sleeve is preferably of sufiicient length to form a support for all of the turns. of the helical element even when the sleeve is in its extended position, as shown in Fig. 3, the part I4 of the sleeve being recessed at I4 so as to telescope over the hub I5 of the driving member when the pinion is disengaged from the driven member I2. The sleeve parts are preferably cut away as shown in Fig. 3, to form interengaging hook portions I3 and I 4" so as to permit the driving arm l3 to be formed integrally with the sleeve I3 and permit the hooking of the driving arminto the loop of the helical element when assembling, the sleeve part. I4 first having been introduced axially into said element.

The driving member I5 is preferably provided with recessed portions or flat spots on one of the arms I5" and the hub I5 as indicated at Hi so as to permit one loop I 6 of the helical element to be inserted longitudinally during the assembly operation, the helical element being moved longitudinally to register the looped ends IS with the sockets I9 after which it is moved transversely to engage the looped ends of the helical element with the sockets.

In Figs. 1 and 2 the parts are illustrated in their normal or idle positions and. are designed for clockwise rotation of the drive shaft I 0 as viewed in Fig. 2. Upon starting the drive shaft, the driving member I5 and helical element I6 rotate therewith. The inertia of the sleeve I3l4 causes it to lag behind with the result that the slot 20 then functions as a guideway to move the driving arm I3 and the sleeve I3I4, longitudinally on the'shaft I9, thereby engaging the pinion I I with the driven member I2 and moving the arm I 3 into engagement with the looped end It" of the element IS. The helical element then transmits the driving torque to the driven member I2, through the driving arm I3, sleeve I3 and pinion II, the helical member contracting against the sleeve I3-,-I4 as shown in Fig. 5. As soon as the engine is started and its speed reaches a point where the driven member I2 drives the pinion I l faster than shaft ID, the pinion is disengaged from the driven member by the action of the helical slot 20 moving the arm I3 longitudinally to the left from the position shown in Fig. 3, back to the position shown in Fig. 1.

To prevent jarring of thepinion along the drive shafta coiled spring 22 may be positioned between the end of the pinion II and a suitable abutment 23, herein shown in the form of an outboard hearing for the shaft I2. This spring serves to hold the pinion out of engagement with driven member I2 when the starter is idle. Preferably the sleeve part I3 is provided with a squared lug 24 which engages the free end of the helical element l6 (Fig. l) to limit the withdrawal movement of the sleeve and thereby maintain the arm I3 in the slot 20.

In Fig. 6, I have illustrated a modified form of helical element It formed of two pieces of material, the attaching ends I 6 being similar to those illustrated in Figs. land 3, but the driving loop or hook Ifi being formed by overlapped hook portions on the two parts.

The provision of a helical spring element with pairs of coils lying close together prevents the coils of flattened wire from tending to tip when under heavy tension, and also permits of the use of a somewhat smaller width of wire as the torque is divided between the two strands. The strands are anchored at opposite sides of the driving member by means of the arm I5 so as to balance the load as Well as to keep the unit in substantially perfect running balance.

It will be apparent that in all positions of the sleeve I3I4 it never passes out from under the coils of the helical element I6, thus at all times forming a seat for the coils of the element to contract against. This effectively prevents collapse of the coils under load. By forming cylindrical sockets in the arms of the driving member the invention is adapted to incorporate either rightor left-hand helical elements.

From the foregoing it will be apparent that the invention contemplates the provision of numerous improvements in engine starters, all of which are of a very practical nature and which materially increase the efficient operation of the device and require the least number of parts. Furthermore by mounting the driving pinion directly on the starting motor shaft, without any intervening sleeve, a pinion of minimum size may be used since the only limitation on the size of the pinion is the size of the motor shaft itself.

I claim as my invention:

1. An engine starter comprising, in combina-: tion with a drive shaft and a driven member operatively connected with the engine, a first power-transmitting element mounted on said shaft for both longitudinal and rotary movement comprising twosleeve-like parts having4 50 and a helical guideway leading from said loop, 60

means securing the other extremity of said second element to said drive shaft, and an arm formed integrally with said first power-transmitting element projecting into said guideway between the convolutions of the spring structure for controlling longitudinal shifting of said power-transmitting element and adapted to engage said loop to form. a driving connection between the two elements, and a lug formed integrally with said first power transmitting element disposed to strike the free end of said coiled spring and limit the withdrawal movement of said first power transmitting element.

2. An engine starter comprising, in combination with a drive shaft and a driven member operatively connected with an engine, a powertransmitting sleeve mounted on said shaft for longitudinal and rotary movement and having pinion teeth on one end arranged to operatively engage said driven member, and means for driving said sleeve and moving the sleeve longitudinally on the shaft comprising a helical spring structure including a double strand of spring wire forming a helical guideway and a driving loop at one end thereof, means anchoring the other end of said spring structure to said shaft at diametrically opposite points so as to rotate the spring structure with the shaft, and a driving arm on said sleeve projecting into said guideway and adapted to be engaged by the looped end of said spring structure to drive the pinion, said sleeve extending through and supporting the entire coiled portion of said spring structure when the starter is operative to sup-port the coils thereof to prevent collapse under load.

3. An engine starter comprising, in combination with a drive shaft and a driven member operatively connected with an engine, a powertransmitting sleeve mounted on said shaft for longitudinal and rotary movement and having pinion teeth on one end arranged to operatively engage said driven member, and means for driving said sleeve and moving the sleeve longitudinally on the shaft comprising a helical spring structure including a double strand of spring wire forming a helical guideway and a driving loop at one end thereof, the attaching ends of said spring structure being formed into rounded eyes, means for anchoring said spring structure to the drive shaft having diametrically opposed cylindrical sockets receiving and substantially surrounding said eyes to retain the same, and an integral driving arm on said sleeve projecting into said guideway and adapted to be engaged by the looped free end of said spring structure to drive the pinion, said sleeve being only slightly smaller than the inner diameter of said spring and extending through the entire coiled portion of said spring structure to support the coils thereof to prevent collapse under load.

4. An engine starter comprising, in combination with a drive shaft and a driven member operatively connected with an engine, a powertransmitting sleeve mounted on said shaft for longitudinal and rotary movement and having pinion teeth on one end arranged in one position of the sleeve to operatively engage said driven member, and means for driving said sleeve and moving the sleeve longitudinally on the shaft comprising a helical spring structure encircling said sleeve with a small clearance including a double strand of spring wire forming a helical guideway and a driving loop at one end thereof, the other ends of said spring structure being formed into rounded diametrically opposed eyes, a driving member secured to said drive shaft and having a pair of diametrically opposed longitudinally extending arms drilled to provide cylindrical sockets for receiving the rounded portions of the spring structure in retaining relationship independently of additional means, said arms being spaced outwardly to clear said sleeve when the sleeve is moved out of engagement with said driven member, and a driving arm on said sleeve projecting into said guideway and adapted to be engaged by the looped free end of said spring structure to drive the pinion.

5. An engine starter comprising, in combination with a drive shaft and a driven member operatively connected with an engine, a helical power-transmitting element surrounding a portion of saidshaft formed to provide a driving loop at one extremity and a helical guideway leading thereto, means securing the other extremity of said element to the drive shaft, an

engine driving element comprising two sleevelike parts positioned on said shaft within said helical element and having complementary hookshaped portions at one end to secure the parts together so that they move as a unit, and a driving arm integral with said engine driving element and, extending therefrom intermediate its ends and into the guideway formed by said helical element. 7

6. An engine starter comprising, in combination with a drive shaft and a driven member operatively connected with the engine, a driving member having a hub by which it is secured rigidly to said shaft and a pair of diametrically opposed longitudinally extending arms spaced radially outwardly from the hub, a helical spring element secured at one end to said armsand providing a helical guide slot and a driving loop at the end of the slot, a sleeve slidable on said shaft within said helical element and having an arm projecting into said slot so as to move the sleeve longitudinally of the shaft during relative rotary movement between the helical element and sleeve, the portion of said sleeve intermediate the arm and said driving member being just slightly smaller than the inner diameter of said spring to support the same under load and received beneath the arms of the driving member when the starter is inoperative, and means on said sleeve adapted to be engaged with the driven member in one shifted position of the sleeve. 7

'7. An engine startercomprising, in combination with a drive shaft and a driven member operatively connected with an engine, a powertransmitting sleeve mounted on said shaft for longitudinal and rotary movement and having pinion teeth on one end arranged to operatively engage said driven member, and means for driving said sleeve and moving the sleeve longitudinally on the shaft comprising a helical spring structure. including a double strand of spring Wire forming a helical guideway and a driving loop at one end thereof, means anchoring the other end of said spring structure to' said shaft at diametrically opposite points so as to rotate the spring structure with the shaft, a driving arm on said sleeve projecting into said guideway and adapted to be engaged by the looped end of said spring structure to, drive the pinion, and a lug on said sleeve positioned to engage the driving loop end of said helical spring structure when the pinion teeth are disengaged from the driven member to limit the longitudinal movement of the sleeve.

8. In an engine starter, in combination, a drive shaft assembly including an element having diametrically o-pposed sockets and a driven member operatively connected with the engine, and a double coil spring structure encircling theshaft to provide a driving connection between the drive shaft assembly and the driven member comprising two strands of spring wire each having a 

